The combination of safe drinking water and hygienic sanitation facilities is a precondition for health as well as for success in the fight against poverty, hunger, child morbidity and gender inequality. It is also central to the human rights and personal dignity of every woman, man and child on earth. Yet 2.6 billion people - half of the developing world - lack even a simple 'improved' latrine. One person in six - more than 1 billion of our fellow human beings - has little choice but to use potentially harmful sources of water. The consequences of our collective failure to tackle this problem are dimmed prospects for the billions of people locked in a cycle of poverty and disease.